Flotation separation of bastnaesite from calcite using a novel Gemini surfactant as the collector

Abstract

The effective separation of bastnaesite from calcium-containing gangue minerals such as calcite is often difficult and the development of more environmentally-friendly and efficient collectors is imperative. A novel cationic Gemini surfactant ethane-1,2-dodecyldimethylammonium bromide (EDDA) was designed and synthesized in the laboratory, and the flotation performance of EDDA was investigated by micro-flotation and artificial mixed minerals experiments. When the EDDA concentration was 1.5 × 10−4 mol/L at pH 7, the grade of REO and the recovery with EDDA were 70.35 % and 88.45 %, respectively. While the grade of REO of NaOL and DDA were only 35.4 % and 44.15 %, indicating that EDDA has excellent selective collecting ability for bastnaesite. The contact angle test depicts that the hydrophobicity of bastnaesite surface enhances while the wettability of calcite surface almost unchanged. The adsorption mechanism was investigated by means of Fourier transform infrared spectroscopy (FTIR), zeta potential and X-ray photoelectron spectroscopy (XPS). The analysis results indicate that EDDA adsorbs on the surface of bastnaesite through electrostatic and hydrogen bonding, and strengthened the surface hydrophobicity of bastnaesite instead of calcite. The study reports the feasibility of applying EDDA for the separation of bastnaesite from calcite.